Evidence and recommendations for tourniquet re-inflation/deflation cycles

Posted on February 21, 2014. Filed under: Tourniquet Re-inflation/Deflation Cycles, Tourniquet Safety | Tags: , , , , , , , |

A hospital recently asked about the existence of evidence and recommendations regarding tourniquet inflation/deflation cycles, after a complicated knee surgery in that hospital lasted 7 hours with three separate inflations of 2 hours, 1 hour 15min. and 40 min. with 30 min. deflation between the first and second inflation and approximately 1 hour deflation between the second and third inflation.

The following excerpts from the existing literature provide information on recommended tourniquet inflation times and re-inflation practices. The excerpts demonstrate that there are no established, evidence-based recommendations for tourniquet re-inflation times and durations. Also evident from these excerpts is any mention of tourniquet pressures, yet there is convincing and well established evidence that higher tourniquet pressure levels and higher tourniquet pressure gradients beneath the cuff are associated with higher probabilities of nerve and soft-tissue injuries [1]. There is also good evidence that lower and safer personalized tourniquet pressure levels and pressure gradients can be achieved through the measurement of the Limb Occlusion Pressures (LOPs) of individual patients [2]. Thus to develop evidence for a best practice, a future study might be warranted in which tourniquet pressure levels and pressure gradients are studied in conjunction with different inflation/deflation/reinflation periods.

     “One way of avoiding ischemic injury to muscle cells may be to employ a so-called tourniquet downtime technique, in which the tourniquet is released for a short period and then is reinflated. However, there is no evidence to support use of this technique, the suggested reperfusion time between successive ischemic periods has ranged from three to twenty minutes47, and time limits for subsequent ischemia are unknown. Furthermore, some authors have questioned the benefit of any tourniquet release and reinflation if the total tourniquet time does not exceed three hours48. In view of this controversy and in the absence of convincing evidence otherwise, we do not recommend a routine tourniquet inflation time of more than two hours. Accurate monitoring and minimization of tourniquet time are recommended.” [1]

     “There is no clearcut rule as to how long a tourniquet may be inflated safely, although various investigators have addressed effects of ischemia on muscle and nerve to define a relatively “safe” period of tourniquet hemostasis. In practice, safe tourniquet inflation time depends greatly on the patient’s anatomy, age, physical status, and the vascular supply to the extremity. Unless instructed otherwise, report to the surgeon when 60 minutes of tourniquet time has elapsed. There is general agreement that for reasonably healthy adults, 90 minutes should not be exceeded without releasing the tourniquet for a short time.

Releasing the tourniquet allows for removal of metabolic waste products from the limb and nourishment of the tissue with oxygenated blood. During this time, elevate the limb 60 degrees to encourage venous return and apply steady pressure to the incision with a sterile dressing. Tissue aeration periods should last at least 10 and preferably 15 minutes the first time and 15 – 20 minutes subsequently. To proceed with the surgery, re – exsanguinate the limb before reinflating the cuff. Take care during this procedure to maintain the sterility of the operative field. No known safe limit to the number of aeration intervals during prolonged tourniquet time has been established.”[3]

     “Even with relatively short tourniquet inflation times (ie, 26 minutes ± eight minutes), researchers have found significant markers of systemic inflammatory response when they were measured 15 minutes after tourniquet deflation.106 Inflation times of 60 minutes for an upper extremity and 90 minutes for a lower extremity have been identified as a general guideline for inflation duration.17 However, some sources indicate that two hours is a safe time limit for tourniquet inflation.20,31 In pediatric patients, inflation times of less than 75 minutes for lower extremities has been recommended.114

Irreversible skeletal muscle damage is thought to begin after three hours of ischemia and is extensive at six hours.115 Allowing intermittent reperfusion restores oxygenation and releases toxins.31 Deflating the tourniquet every two hours with at least a 10-minute reperfusion time has been identified as a strategy to consider to decrease the risk for tissue damage.28 Another approach is to release the tourniquet after 90 minutes for at least 10 to 15 minutes for the first reperfusion period, then 15 to 20 minutes for each subsequent reperfusion period.17 However, it has also been reported that implementing reperfusion periods after 60 to 90 minutes of ischemia can contribute to muscle injury. 23 ”[4]

     “The practice of using breathing periods represents an attempt to reduce ischaemic injury. This involves releasing the tourniquet after a set period of ischaemia to allow reperfusion, with the aim of returning tissue to its pre-ischaemic state, before subjecting the limb to a further period of ischaemia. Several studies have defined the appropriate breathing periods for the time ischaemia is required.

Pedowitz, using technetium uptake, found in a rabbit model that with a tourniquet time of four hours, skeletal muscle injury beneath the cuff was reduced significantly by hourly ten minute reperfusion intervals.11 He noted that a ten-minute reperfusion period after a two-hour tourniquet tended to exacerbate muscle injury. Reperfusion intervals could prolong the duration of anaesthesia, increase blood loss, or produce haemorrhagic staining and oedema.12 Nevertheless, Sapega and colleagues recommended on the basis of studies on dogs that ischaemic injury to muscle can be minimised by limiting the initial period of tourniquet time to 1.5 hours.13 Release of the tourniquet for five minutes permitted a further period of 1.5 hours. With knowledge of the ischaemia–reperfusion syndrome, the use of breathing periods is not logical, as reperfusion is now recognised as a major cause of damage to limbs after ischaemia. Further damage by free-radical-mediated mechanisms is likely even after the biochemistry of the venous blood returns to normal equilibrium. Work in animals has suggested that allowing reperfusion may actually increase the amount of damage to the ischaemic limb in certain structures.14  ”[5]

 

References:

A PDF containing selected excerpts from the references below can be found here

[1] Noordin S, McEwen JA, Kragh JF Jr, Eisen A, Masri BA. Surgical tourniquets in orthopaedics. J Bone Joint Surg Am. 2009;91(12):2958-2967.

[2] Younger AS, McEwen JA, Inkpen K. Wide contoured thigh cuffs and automated limb occlusion measurement allow lower tourniquet pressures. Clin Orthop Relat Res. 2004 Nov;(428):286-93.

[3] McEwen JA. Tourniquet use and care. http://www.tourniquets.org/use_care.php

[4] Recommended practices for care of patients undergoing pneumatic tourniquet-assisted procedures. In: Perioperative Standards and Recommended Practices. Denver, CO: AORN, Inc; 2013; p. e25-e50.

[5] Klenerman L. The Tourniquet Manual Principles and Practice. London: Springer; 2003.

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Safety and Efficacy Advances in Surgical Tourniquets

Posted on November 22, 2013. Filed under: Safety and Efficacy Advances | Tags: , , , , , , , , , , , , |

Jim McEwen PhD

 

New AORN Recommended Practices for Surgical Tourniquets

All surgical tourniquet users should be aware that on June 15, 2013 the AORN (Association of periOperative Registered Nurses) published a major update of its recommended practices on pneumatic tourniquet used in surgery.   These guidelines are widely used and followed, especially in accreditation of surgical facilities.  Many changes in recommended practices have been made, and new topics have been added, as outlined below and as given at http://www.tourniquets.org .   The RP is available for purchase at http://aornstandards.org/.

 

Comparative Effectiveness  

Outpatient surgical staff and facilities are paying increased attention to ‘comparative effectiveness’.   Comparative effectiveness research (CER) is a method of comparing different devices and treatments to determine which is the most effective.  The growth of CER highlights the value of research and published evidence quantifying the benefits of medical devices, and a growing body of evidence supports recent advances seen in surgical tourniquet instruments, cuffs and accessories.  Updated information on recent publications and evidence can be found at www.tourniquets.org and in the 2013 AORN Recommended Practices.

Two disturbing developments related to comparative effectiveness have occurred recently.  First, counterfeit tourniquet products have been seen. These counterfeit products have markings and appearances that mimic existing, proven and authentic products, but their quality, performance and safety are suspect or unknown.  Second, cloned tourniquet products have been seen in some countries.  While cloned products do not bear counterfeit markings, the fact that their physical appearance is similar to authentic products may lead users to mistakenly believe that their safety, quality and effectiveness will be equivalent.  This is not the case.  In considering comparative effectiveness, it is critical that surgical facilities and staff verify the origin and authenticity of tourniquet products.

 

Personalized Tourniquet Pressure Settings

It is well established by evidence in the clinical literature that higher tourniquet pressures are associated with higher probabilities of tourniquet-related injuries.  As a result, modern tourniquet systems aim to use the minimum pressure required to stop blood flow in a limb over the duration of a surgical procedure.  A new method based on Limb Occlusion Pressure (LOP) has been shown to allow individualized, optimal tourniquet pressure settings to be achieved.  LOP  can be defined as the minimum pressure required, at a specific time in a selected tourniquet cuff applied to an individual  patient’s limb at a desired location, to stop the flow of arterial blood into the limb distal to the cuff.   Some advanced surgical tourniquet systems include means to measure LOP automatically, although LOP can also be measured non-automatically by users.   Further information can be found at http://tourniquets.org/lop.php.

 

Personalized Tourniquet Cuffs

A recent introduction of personalized tourniquet cuffs has also resulted in safer and more effective tourniquet use.  Personalized cuffs are designed to better match patient limb size and shape and thus provide more efficient application of cuff pressure to the limb, allowing lower and safer tourniquet pressures to be used.  The improved fit is a result of the advent of new types of tourniquet cuff designs, in addition to the traditional tourniquet cuff design.  The traditional ‘straight’ tourniquet cuffs are best suited to cylindrical limb shapes.   New types of cuffs are ‘variable contour cuffs’ and allow the user to adapt the shape of the tourniquet cuff to any of a wide range of non-cylindrical (or tapered) limb shapes.  In addition the advent of new cuffs that allow better matching of cuff shapes to individual limb shapes, other advances in tourniquet cuff design have been made for pediatric and bariatric patient populations.  Tourniquet cuffs are now available that are matched specifically to pediatric and bariatric limb sizes and shapes, with comparative effectiveness established in published literature.

 

Reducing Soft Tissue Injuries with Matching Limb Protection Sleeves

High pressures, high pressure gradients and shear forces applied to skin and soft tissues underlying a tourniquet cuff can cause injuries to the skin and soft tissues.  To reduce the nature and extent of these injuries, studies have been published to determine the relative effectiveness of no protective material, underlying padding, underlying stockinette, and underlying limb protection sleeves that are matched to specific limb sizes and cuff sizes.  Study results present evidence that limb protection sleeves improve safety by protecting the skin underlying tourniquet cuffs during tourniquet use, and further provide evidence that greatest safety is achieved through the use of limb protection sleeves consisting of two-layer material specifically matched to the limb size and cuff size.  (See further information at www.tourniquets.org)

 

Reprocessing tourniquet cuffs

Outpatient surgical facilities are increasingly facing the question of whether, when, and how to reprocess tourniquet cuffs.  The answer requires consideration of patient safety, risk management, and cost.

For tourniquet cuffs designated as ‘reusable’ by manufacturers, the answers are straightforward because instructions on cleaning, inspecting and testing cuffs between uses are usually provided by the manufacturers.  Some facilities are reprocessing and reusing tourniquet cuffs designated as being ‘disposable’ or ‘single use’ by the manufacturers.  In such cases, no instructions on cleaning, inspecting and testing cuffs between uses are provided by the manufacturers.  For any facility considering the reprocessing and reuse of disposable or single-use cuffs, the following precautions should be taken.

  • A tourniquet cuff testing program should be established so that each cuff is thoroughly tested according to a written protocol after each use, and prior to the next use, with the results thoroughly documented.
  • A unique identifier should be used for each cuff so that the number of reuse cycles can be recorded.
  • Each cuff should be replaced after a maximum number of reuse cycles has been reached, to reduce the risk of cuff failure and patient injuries during use.
  • A tourniquet cuff testing protocol should be established in accordance with the recommendations of the original manufacturer of the cuff. At a minimum, the cuff testing protocol should include:

(a) a leak test, including inflating the cuff to a maximum pressure recommended by the manufacturer for a period of time, with the cuff wrapped around a test mandrel or laid flat,
(b) a fastener integrity test, to assure that the fasteners are not degraded to the point of being unsafe at the maximum pressure specified by the manufacturer,
(c) a physical inspection of the cuff to detect blockages of the pneumatic passageway in any portion of the inflatable bladder or tubing due to reprocessing damage or fluid entry,
(d) a visual inspection of the cuff to detect damage or deterioration, including: any warping of stiffener due to inappropriate reprocessing; discoloration or contamination of the cuff surface; damage or deterioration of the cuff connector or inflatable portion; and
(e) written documentation and evaluation of the test results before a decision is made regarding cuff reuse.

The complexity and cost of implementing an appropriate tourniquet cuff testing program may mean that the safe reprocessing of single-use tourniquet cuffs may not be cost-effective.

  

Emergency and military tourniquets

Some outstanding work by the US Army’s Institute for Surgical Research has led to the introduction and widespread use of tourniquets in combat settings.  It has been proven convincingly that many lives have been saved that would have been lost without the use of tourniquets.   As a result of these successes in combat settings, the same types of tourniquets are now being used increasingly by police, paramedics and other first responders in non-military settings with similar benefits.    Also, based on the proven safety and efficacy of pneumatic tourniquets in surgical settings over many years, new types of compact pneumatic tourniquets are being developed and used in emergency and military settings.  For example, a recent study of comparative effectiveness led to the introduction and use of pneumatic tourniquets by NATO forces. (See http://www.tourniquets.org for more information.)

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Hazards of Hemaclear Elastic Ring Tourniquets

Posted on September 18, 2012. Filed under: Silicone Ring Tourniquets, Tourniquet Safety | Tags: , , , , , , , , , , , |

This article discusses hazards and limitations associated with the use of a Hemaclear elastic ring as a tourniquet.

The Hemaclear elastic ring has been shown to apply high pressure levels and high pressure gradients to the underlying limb and soft tissues [1, 2].  Such high pressure levels and high pressure gradients produced by this elastic ring have resulted in reports of high levels of pain [3, 4, 5].  In addition to pain, evidence in the published literature has shown that higher pressure gradients and higher pressure levels in tourniquets are associated with higher probabilities of injuries to underlying nerves and soft tissues [2,6].

Elastic tourniquets were used as tourniquets in the nineteenth century.  However, their use was abandoned early in the twentieth century because of many recurring reports of serious nerve and soft tissue injuries resulting from elastic tourniquets, including permanent limb paralysis.  They were replaced by pneumatic tourniquet systems which safely and reliably stop arterial blood flow at much lower tourniquet pressures and lower tourniquet pressure gradients [2,6].

Related hazards and limitations associated with recent efforts to re-introduce a non-pneumatic elastic ring as a tourniquet include the following.

1. The Hemaclear elastic ring does not measure the actual tourniquet pressure applied to the limb, nor does it measure the pressure gradient applied to the patient’s limb.

2. Thus a Hemaclear ring cannot provide the user with an accurate indication of the actual tourniquet pressure and pressure gradient applied to the patient’s limb.

3. There is no documented evidence of the actual pressure levels and pressure gradients applied to limbs by each size of Hemaclear elastic rings.

4. It is not possible to control the pressure applied by the Hemaclear elastic ring to the patient’s limb during a surgical procedure.

5. The surgical user is left with no practical contingency plan in the event of arterial bleeding in the limb distal to the Hemaclear ring during surgery, other than finding and cutting off the ring, and then using a pneumatic tourniquet.

6. Use of a Hemaclear elastic ring is impractical if there is a need for reperfusion of the limb during a long procedure that is typical of revision surgery.

7. Although the Hemaclear elastic ring has had very limited usage in the US to date, problems and hazards associated with this limited usage have already been reported to the FDA. For example: Report of Severe Pain and Report of Skin Tearing.

References (VIEW DETAILS)

[1] McEwen JA, Casey V. “Measurement of hazardous pressure levels and gradients produced on human limbs by non-pneumatic tourniquets.”  Proc 32nd Can Med Biol Eng Conf. 2009, pp 1-4.

[2] Noordin S, McEwen JA, Kragh JF Jr, Eisen A, Masri BA. “Current Concepts Review: Surgical Tourniquets in Orthopaedics.” J Bone Joint Surg Am. 2009; 91:2958-67.

[3] Smith OJ, Heasley R, Eastwood G, Royle SG. “Comparison of pain perceived when using pneumatic or silicone ring tourniquets for local anaesthetic procedures in the upper limb.” J Hand Surg Eur. 19 June 2012. DOI: 10.1177/1753193412449116

[4] FDA Report 1, FDA Report 2

[5] Report to FDA MedWatch on the Hemaclear elastic ring tourniquet, 2009

[6] McEwen JA. “Complications of and improvements in pneumatic tourniquets used in surgery.” Medical Instrumentation. 1981;14(4):253-7.

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